Ornithosaurian

Part of speech: noun, adjective

Definitions

1. Relating to the ornithosaurs, a group of extinct reptiles that includes the pterosaurs and the bird-like dinosaurs
2. Of or belonging to an extinct order of archosaurian reptiles, often associated with flying or bird-like forms
3. Characteristic of the ornithosaurs, a reptilian lineage of extinct animals sometimes grouped with early birds

Etymology: Ornithosaurian comes from the Greek "ornis" (bird) and "sauros" (lizard), and the name it describes was itself a mistake. In 1887, the English palaeontologist Harry Govier Seeley proposed the group Ornithosauria for the flying reptiles later called pterosaurs, having decided that their wing structure showed they were close kin to birds. The name stuck even after the idea was dropped, so the creatures remain "bird-lizards" in name, though they were never birds and were not closely related to them. The word came into use in English in the late nineteenth century, as a coinage from the scientific Greek roots rather than an inherited or ancient term. Like many such formations, it was built to sort fossils into a classification, so its ancient-sounding parts disguise a Victorian date. Seeley's theory had several supporters, but later fossil discoveries showed that pterosaurs belonged to a separate lineage of archosaurs, which is why the name now survives mainly as a relic of an early classification.